of codfish.  The house fly is said to have 20,000,000 descendants in a season, counting several generations of progeny, from its several broods.  And some scientist has computed that the aphis, or plant-louse, breeds so rapidly, and in such enormous quantity, that the tenth generation of one set of parents would be so large that it would contain more ponderable animal matter than would the population of China, which is estimated at 500,000,000!  And this without counting the progeny preceding the tenth generation!

The result of the above conditions is very plain.  There must ensue a Struggle for Existence, which necessitates the Survival of the Fittest.  The weak are crushed out by the strong; the swift out-distance the slow.  The individual forms or species best adapted to their environment and best equipped for the struggle, be the equipment physical or mental, survive those less well equipped or less well adapted to environment.  Animals evolving variations in structure that give them even a slight advantage over others not so favored, naturally have a better chance to survive.  And this, briefly, is what Evolutionists call “The Survival of the Fittest.”

As appertaining to the Struggle for Existence, color and mimicry are important factors.  Grant Allen, in his work on Darwin, says concerning this, and also as illustrating “Natural Selection”:  “In the desert with its monotonous sandy coloring, a black insect or a white insect, still more a red insect or a blue insect, would be immediately detected and devoured by its natural enemies, the birds and the lizards.  But any greyish or yellowish insects would be less likely to attract attention at first sight, and would be overlooked as long as there were any more conspicuous individuals of their own kind about for the birds and lizards to feed on.  Hence, in a very short time the desert would be depopulated of all but the greyest and yellowest insects; and among these the birds would pick out those which differed most markedly in hue and shade from the sand around them.  But those which happened to vary most in the direction of a sandy or spotty color would be more likely to survive, and to become the parents of future generations.  Thus, in the course of long ages, all the insects which inhabit deserts have become sand-colored, because the less sandy were perpetually picked out for destruction by their ever-watchful foes, while the most sandy escaped, and multiplied and replenished the earth with their own likes.”

Prof.  Clodd, remarking upon this fact, adds:  “Thus, then, is explained the tawny color of the larger animals that inhabit the desert; the stripes upon the tiger, which parallel with the vertical stems of bamboo, conceal him as he stealthily nears his prey; the brilliant green of tropical birds; the leaf-like form and colors of certain insects; the dried, twig-like form of many caterpillars; the bark-like appearance of tree-frogs; the harmony of the ptarmigan’s summer plumage with the lichen-colored stones upon which it sits; the dusky color of creatures that haunt the night; the bluish transparency of animals which live on the surface of the sea; the gravel-like color of flat-fish that live at the bottom; and the gorgeous tints of those that swim among the coral reefs.”